Synchronizing mechanism



Jan. 24, 1928. 1,656,962

E. A. SPERRY SYNCHRONIZING MECHANISM Filed Sept. 18. 1920 53 woe/M4101Patented Jan. a4, 1928.

v 1,656,962 PATENT OFFICE.

ELMER A. SPERRY, OF BROOKLYN, NEW YORK, ASSIGNOR TO THE SPEBRY GYROSGOPECOMPANY, OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK.

SYNCHBONIZING- MECHANISM.

Application filed September 18, 1920. Serial No. 411,819.

This invention relates to means for maintainingsynchronism between aplurality of movable members. More particularly it is concerned with theprovision of reliable and eiiicient means for insuring the driving of amember at a constant speed and in synchronism with a constant speeddevice such as a clockwork mechanism. My invention will be found to beespecially'useful when applied. to the constant speed rotation oftelescopes in observatories, where, for example, it may be desired tocause constant speed rotation of'a telescope through one revolution perday. However, it will be apparent that my invention is of generalapplication and may be employed wherever it is desired to maintain onemember in synchronism with another.

Further objects and advantages will ap-- pear as the description of theinvention is hereinafter developed.

Referring to the drawings wherein I have shown what I now consider to hethe preferred form of my invention:

Fig. 1 is a view in elevation of the synchronizing mechanism, partsbeing broken away.

Fig. 2 is a view in sectional elevation taken on line 2-2 of Fig. 1.

Fig. 3 is a view of a detail.

Fig.4 .is a view in elevation showing the mechanism of Fig. 1 applied toa driven member for controlling the speed thereof, certain partsappearing in section.

Fig. .5 is a wiring iagram. Fig. 6 is a detail showing a different p0-sition of the parts shown in Fig. 1.

The driven member 1 is shown mounted on a shaft -2 which may be rotatedby any suitable means. For purposes of illustration I have'shown saidshaft as driven by a motor 3, through the medium, of a shaft 4, worm 5,and worm wheel 6. It will, of course, be understood that motor 3 candrive, through worm wheel 6 or otherwise, a telescope or any otherdevice which it may be desired to rotate at a definite and constantspeed. For maintainin constant the speed of motor 3, and hence o themembers driven thereby, a speed responsive governor may be providedcomprising a pair of weighted arms 7, 7 fixedly connected at one endeach to shaft 4, and at their other ends to a sleeve 8 slidable on saidshaft 4. Said sleeve 8 has attached thereto a conta t. 9

winding 16. Aresistance 17 is in series with armature 15 and isconnected at its terminals with contacts 9 and 10 as shown in Fig. 5. Inthis manner, said resistance isshort circuited when contact *9 engagescontact 10, and is placed in series with the armature 15 when saidcontacts are separated. By this means, as will ,be readily understood,the speed of rotation of shaft 4 is kept constant. Obviously, theposition of contact 10 determines the normal speed of the motor, forexam le, the more it' is moved to the right in ig; 4, the h gher thenormal speed of the motor, since a greater speed must be attained tocause the governor to separate contacts 9 and 10 to cut in theresistance 17 The operation of this device is obvious, for the positionof contact 10 determines the amount of bowing of springs 7 of thegovernor initially. As soon as the shaft 4 rotates, the weights carriedby the leaf springs 7 would normally tend to fly outwardly and causecontact 9- to break away from contact 10, but this tendency of theweights to fly outwardly is opposed by the tension of springs .7 whichis greater the more said sprmgs are bowed. The shaft 4 will thereforehave to rotate at such a contact 9 is separated from contact 10. Ob-

viously, therefore; moving contact 10 to the right or left in Fig. 4,will give a greater or lesser initial bend or bowing to springs 7 andhence, a greater or lesser resistanceto the centrifugal force of theweights carried by said springs, so that the shaft 4 will have to rotateat greater orlesserspeed before said contact 9 is moved out ofengagement with contact 10. i i

The driven member or arm 1 may be provided at one end with a trolley 18adapted to traverse a circular track member 19 of insu latmg materialand provided with contact members 20, 20'. Said track member 19 is shownmounted on a suitable support 21.

. Said contacts 20, 20 may be arranged in any suitable or desired manneron trackway 19, but for purposes of illustration I have shown thempositioned diammetrically opposite each other on said trackway. It willbe ap parent that as arm 1 is rotated through one revolution, trolley 18is brought into engagement with said contacts 20 and 20 successively.

I prefer that the movement of arm 1 be kept in sy'nchronism with amaster regulator 22 which may be an accurate clock, as shown. To thisend I have shown contacts 23, 23 in the path of movement of the minutehand 24 of clock 22 and positioned similarly to contacts 20, 20'. Bythis arrangement if minute hand 24 and arm 1 are moving in synchronism,said minute hand will engage one of contacts 23, 23 at the same timethat trolley 18 engages the corresponding one of contacts 20, 20. If,however, said minute hand and arm are not in synchronism, the minutehand will-engage one of contacts 23, 23 before or after trolley 18engages the corresponding one of contacts 20, 20, In

.order to bring the parts driven by motor 3' into synchromsm withclockwork 22, so that they will be driven at the desired rate of speed,I have provided means brought into action when minute hand 24 andtrolley 18 fail to engage their respective contacts simultaneously formoving the threaded member 25 to vary the position of contact 10 andthus change the slpeed of motor 3. Such means is shown in igs. 1-4,inclusive, and may be constructed substantially as follows:

Member 25 is threaded through a ratchet wheel 26 internall threaded tocooperate with the threads oi member 25, and having two sets of ratchetteeth, extending in op posite directions. Ratchet wheel 26 mountedbetween a pair of standards, 27, which standards support the member '25.Removable cap pieces 28 may be fitted over member 25 and secured to thestandards 27, as shown. Rotation of member 25 in standards 27 may beprevented in any suitable manner, as by providing on member 25 a groove29 designed to cooperate with a spline or key on one of cap ieces 28. Inthis manner it will be seen. t at rotation of ratchet wheel 26 in onedirection or another will move member 25 longitudinally eitherbackwardly or forwardly.

Pivot 11y mounted on cross piece 30 of the framew rk of thesynchronizing mechanism is a member 31 provided at one end with apendulum 32 and on opposite sides of its other end with 'armatures 33,33' 'adapted .to cooperate respectively with solenoids or electromagnets34, 34'. Between its pivotal connection and pendulum bob 32, the member31 is provided with oppositely extending arms 35, 35' to which awls 36,36' respectively,

are pivoted. Sai pawls, as shown, are designed to cooperate with theteeth of ratchet wheel 26 to move said wheel in one direction oranother.

As shown in Fig. 5, electromagnet 34 is connected in circuit withcontacts 23, 23', while electromagnet 34 is in circuit with contacts 20and 20, said magnets being connected, through means to be describedlater, with one terminal of battery 50. Minute hand 24 and arm 1 are, asshown, connected with the other terminal of said battery. It

will now be seen that, if the minute hand 24 and arm 1 are moving insynchronism, so that said hand 24 and trolley 18 simultaneously engagecorresponding contacts, mag

nets 34 and 34 will be energized -simultaneously and will have no effecton member 31 and pawls 36, 36. Suppose, however, that minute hand 24engages contact 23 before trolley 18 engages contact 20. Magnet 34 isthereupon energized and armature 33 I attractedZto the left in Fig, 1.Pawl 36 is thereby moved to the right to turn ratchet wheel 26clockwise. Turning of said ratchet wheel in said direction moves screwthreadedretract threaded member 25, whereupon thev resilient member 11will follow said member 25, being either normally biased into engagementtherewith or suitably attached thereto, so that contact 10 will be movedto the left as viewed in Fig. 4 and decreased centrifugal force willsuflice to disengage contact 9 from contact 10. The speed of motor 3 isthereby decreased.

Assuming that the minute hand 24 has engaged contact 23 before trolley18 engages contact 20 and that ratchet wheel 26 has thereby been turnedto move contact 10 to the left, it will be seen that some means must beprovided for reventing movement of ratchet wheel 26 1n the oppositedirection by the energization of magnet 34, when trolley 18 next engagescontact 20. Without such means, the motor 3 would merely be momentarilyspeeded up when minute hand 24 engaged contact 23, and then, whentrolley 18 engaged contact 20, the speed of said motor would be restoredto its original value. In order to prevent this I. have provided meansfor retainin member 31 in the position to which it has been moved by onemagnet until atter the other magnet has been 139 behind said pawls whenthe latter are moved from under their respective levers, I have shownsaid levers as provided with weights 38, 38'. Stops 39, 39' are providedto limit the downward movement of said levers. While various means maybe provided for returning levers 37, 37 to their original positionsafter they have remained behind their respective pawls for a suflicientlength of time, I prefer to utilize the following mechanism:

Pivoted to link 40 is an arm 41 which extends from said link to a pointadjacent lever 37 as shown in Fig. 1. Said arm 41'is provided with ahooked extremity 42 and may be guided by a suitable bracket 43 attachedto supports 13. Aspring44maybe attached to bracket 43 and'bear at oneend against arm 41 to hold the latter normally in engagement with a pinor stop 45 carried by said bracket. Suitable endwise play is providedfor arm 41 between pin 45 and the end of bracket 43 for a purpose whichwill appear later. The link 40 is pivoted as shown to standards 27 andrests normally on a pin 46 mounted in opposite supports 13. Said link 40is provided with an armature 47 adapted to be attracted by anelectroma'gnet 48 suitably mounted on one or more of said supports -13.Associated with lever 37 are elements similar to elements 40-48,inclusive,

and designated by the same numerals with a prime added. U V

As shown in Fig. 5, 'fnagnet 48' is in'circuit with magnet 34," whilemagnet 48 is in circuit with magnet 34. Assuming-now that minute hand 24engages contact 23 before trolley .18 engages contact 20, magnets 34 and48' will be energized. Pawl 36 isthereby swung to turn ratchet wheel 26and when said pawl has reached the limit of its movement lever 37 dropsupom pin 39 into the positiomshown in Fig.6, and prevents return of saidpawl and of arm 31 to their original positions. Atthe' same time that.pawl 36 is moved, link 40 is; attracted by magnet 48 thereby moving arm41' upwardly. Said arm, however, on engagin lever 37 will merely bepushed back in racket 43" a ainst spring 44'; suitable play being provied for said arm in said bracket as has been pointed out in connectionwith arm 41 and bracket 43. As soon as minute hand 24 passes out ofengagement with contact 23, magnets 34 and 48' are'deenergized. Pendulum32 cannot return pawl 36 and arm 31 to their original positions,however, since lever 37 has dropped behind said pawl. Link 40 and arm41' will drop back to their original positions. Now, a moment or solater, when trolley 18 engages contact 20, magnets 34 and 48 areenergized. However, since lever 37 is still behind pawl 36, arm

31 cannot move in.response to energization' of magnet 34, and henceratchet wheel 26 is not moved. Arm 41 is moved upwardly by magnet 48,all parts finally assuming the position shown in Fig. 6, wlth hooked end42 overlying lever 37. During movement of arm 41 past lever 37, ofcourse, said arm was forced backwardly in bracket 43 when the beveledportion of end 42 engaged lever 37, but upon said beveled and clearingsaid lever, spring 44 snapped said lever into the illustrated position,as will readily be seen. Now, when trolley 18 passes out of engagementwith contact 20, magnets 34 and 48 are deenergized, and arm 41 dropsdownwardly to its original position, thereby moving lever 37 from enagement with pawl 36. Pendulum bob 32 thereupon moves arm 31 and pawl 36to their positions shown in Fig. 1. Arm 41,

lever 37, and pawl 36 thus assume their positlons shown in Fig. 1 andthe synchronizing mechanism is ready for another cycle. If now, eithermagnets 34 and 48' or 34 and 48 should subsequently be energized, asimilar cycle will occur. If desired, a spring 49 may be employed toassist in returning link 40 and arm 41 to their normal positions, and asimilar spring49 may be employed in connection with link 40 and arm 41'.Springs 53, 53 may also be employed, as shown, to positively force pawls36, 36' downwardly'into engagement with ratchet wheel 26.

In Fig. 5, I have shown thermotor 3 and magnets 34, 34, 48, 48 incircuit with a suitable source of E. M. F. such as a battery 50. Ifdesired, means may be provided for automatically breaking the circuit inwhich the aforesaid magnets are located whenever motor 3 for any reasonstops running. For this purpose'I'have shown in Fig. 5 a pair ofcontacts51 and 52 connected in the circuit from said magnets to battery,50. Contact 51 is carried by resilient member l1,.as

moves backwardly a suflicient amount for resilient member 11 to bringcontact 51 again into engagement with contact .52, so thatthe clockcircuit is again rendered operative. As shown in Fig. when contacts 51,52 are used, the member 25 may engage the resilient arm llat a pointbelow contact 10, so that the pressure of the governor may spring arm 11to open said contacts 51, 52.

The operation of my device will now be clear and may be brieflysummarized as follows: As long as arm 1 and minute hand 24 move insynchronism, magnets 34 and 34' are energized simultaneously and thespeed of motor 3 is not changed. If, however, the speed of the motor isnot such as to drive arm 1 atexactly the speed of minute hand 30, one orthe other of magnets 34, 34 will be energized to cause movement ofcontact and consequently change the speed of said motor. For example, ifminute hand 24 engages contact 23 before trolley 18 engages contact 20,magnet 34 is energized and contact 10 is moved forward to increase thespeed 0t said motor. Subsequent deenergization of said magnet 34, andenergizationof ma net 34' by engagement 1 of trolley 18 wit 1 contact20, does not change the speed of the motor but merely places thesynchronizing mechanism in condition for another cycle. If, when minutehand 24 engages contact 23', trolley 18 is not in engagement withcontact 20' the speed of motor 3 is again changed. In this way the speedof motor 3 is automatically maintained such as to drive member 18 insynchronism with minutehand 24. It is, of course, understood that motor3 may be brought nearly to the desired speed by external means wellknown in the art and that the synchronizing means which -I have shownmay then be em loyed to bring the motor exactly to the desired speed andmaintain it automatically at such speed. For a given adjustment ofcontact 10 with respect to contact 9, the motor 3, of course,

runs at a constant speedand the speed responsive governor maintains suchspeed until said adjustment is changed by the synchronizing mechanism,

In accordance with the provisions of the patent statutes, I have hereindescribed the principle of operation of my invention), together with theapparatus which I now consider to represent the best embodiment thereof,but I desireto have'it understood that the apparatus shown is onlyillustrative and that the invention can be carried out by other means.Also, while it is designed to use the various features and elements inthe combination and relations described, some of these may be alteredand others omitted without interfering with the more general resultsoutlined, and theinvention extends to such use.

Having described my invention, what I claim and desire to secure byLetters Patent vis: 4

1'. In combination, a plurality of rotatable members, contactspositioned at certain points in the respective paths of travel of saidmembers, means brought into action by engagement of one of said memberswith its contact at a time when another of said members is disengagedfrom its corresponding contact for varying the speed of rotation of oneof said members, and means brought into action by the subsequentengagement of said other member with its contact for restoring saidfirst named means to its normal position without varying the speed ofany of said members.

2. In combination, a motor, a member rotated thereby, a second rotatablemember, means for maintaining said members ins 'nchronism, and means forrendering the rst mentioned means inoperative whenever the speed of saidmotor falls below a predetermined amount.

3. In combination, a .motor, a member rotated thereby, a secondrotatable member, electrical means controlled by said members forsynchronizing the same, and means for automatically rendering saidelectrical means inoperative whenever the speed of said motor fallsbelow a predetermined amount.

4. In a synchronizing mechanism, in combination an adjustable member,-amovable element, means for moving said element in either of oppositedirections, means res onsive to movement of said element for ad ustingsaid member, means rendered operative upon movement of said element inelther of said directions for preventing return of said element to itsnormal position, and automatic means for rendering inoperative saidpreventing means.

5. A synchronizing mechanism comprising in combination an adjustablemember, means including a movable element for adjusting said member ineither of opposite directions, means for holding said element in a givenposition to prevent adjustment of said member for a given time, andmeans for automatically releasing said element.

6. In combination, a motor, means for varying the speed of said motor,means for preventing actuation of said first mentioned means for a giventime, and means for automatically rendering said preventing meansinoperative.

7. In a synchronizing device, a movable member, means for moving saidmember in one direction, means for moving said membeer in anotherdirection, means responsive to .movement of said member in one directionfor preventing return of said member to normal position, and means forautomatically releasing said member after the means for moving saidmember in said other direction has been brought into operation.

8. In a synchronizing device, a movable member, an electromagnet formoving said member in one direction, a second electromagnet for movingsaid member in another direction, means responsive to movement of saidmember by one of said electroniagnets for preventing return of saidmember to normal position, and means for automatically releasing saidmember after the other electromagnet has been energized.

9. In combination, a motor, means including an adjustable element forvarying the speed of said motor, a movable member, means for moving saidmember in one direction, means for moving said member in anotherdirection, means controlled by said member for adjusting said element,means responsive to movement of said member in one direction forpreventing return of said member to normal position, and means forreleasing said member after the means for moving said member in saidother direction has been brought into operation.

10. In a synchronizing device, two movable members, means for varyingthe speed of one of said members, a separate means for each of saidmembers whereby each of said members may operate said first named means,means for energizing both of said last named means simultaneously inopposite directions to prevent actuation of said first named means whensaid members are in synchronism, and means whereby one of said secondnamed means actuates said speed varying means whenever said members areout of synchronism.

11. In a synchronizing device, two movable members, means for varyingthe speed of one of said members, a separate means for each of saidmembers whereby each of said members may operate said first named means,means for energizing both of said last named means simultaneously inopposite directions to prevent actuation of said first named means whensaid members are in synchronism, and means whereby one of said secondnamed means actuates said speed varying means whenever said members areout of synchronism, until synchronism is reestablished.

12. In a synchronizing device, two movable members, means for varyingthe speed of one of said members, a separate means for each of saidmembers whereby each of said members may operate said first named means,means for energizing both of said last named means simultaneously in oposite directions to prevent actuation of sai first named means when saidmembers are in synchronism, means whereby one of said second named meansactuates said speed varying means whenever said members are out ofsynchronism and means for maintaining one of said second named meansoperative and the other of said means inoperative until synchronism isreestablished.

13. In a synchronizing device, two movable members, means for varyingthe speed of one of said members, a separate means for each of saidmembers whereby each of said members may operate said first named means,means for energizing both of said last named means simultaneously inopposite directions to prevent actuation of said first named means whensaid members are in synchronism, means whereby one of said second namedmeans actuates said speed varying means whenever said members are out ofsynchronism, means for maintaining one of said second named meansoperative and the other of said means inoperative until synchronism isreestablished, and means whereby said other member renders saidoperative means inoperative whenever synchronism is reestablished.

'In testimony whereof I have aiiixed my signature.

ELMER A. SPERRY.

